@stdlib/stats
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Standard library statistical functions.
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{{alias}}( x, k )
Evaluates the natural logarithm of the probability density function (PDF)
for a chi distribution with degrees of freedom `k` at a value `x`.
If provided `NaN` as any argument, the function returns `NaN`.
If provided `k < 0`, the function returns `NaN`.
Parameters
----------
x: number
Input value.
k: number
Degrees of freedom.
Returns
-------
out: number
Evaluated logPDF.
Examples
--------
> var y = {{alias}}( 0.3, 4.0 )
~-4.35
> y = {{alias}}( 0.7, 0.7 )
~-0.622
> y = {{alias}}( -1.0, 0.5 )
-Infinity
> y = {{alias}}( 0.0, NaN )
NaN
> y = {{alias}}( NaN, 2.0 )
NaN
// Negative degrees of freedom:
> y = {{alias}}( 2.0, -1.0 )
NaN
// Degenerate distribution when `k = 0`:
> y = {{alias}}( 2.0, 0.0, 2.0 )
-Infinity
> y = {{alias}}( 0.0, 0.0, 2.0 )
Infinity
{{alias}}.factory( k )
Returns a function for evaluating the natural logarithm of the probability
density function (PDF) of a chi distribution with degrees of freedom `k`.
Parameters
----------
k: number
Degrees of freedom.
Returns
-------
logpdf: Function
Logarithm of probability density function (PDF).
Examples
--------
> var mylogPDF = {{alias}}.factory( 6.0 );
> var y = mylogPDF( 3.0 )
~-1.086
See Also
--------